Nonicing carburetor



Nov.. 5', 1946. M. BlcKNEl- L NONICING CARBURETOR Filed June'24, 1943 Patented Nov.y 5, 1946 NONICIN G CARBURETOR George M. Biokneu, st. Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo.. a corporation of Delaware Application June 24, 1943, serial No. 492,146

This invention relates to carburetors for `in ternal combustion engines and consists particularly in novel meansfor delivering metered fuel to the mixture conduit substantially posterior to` the throttle valve for idling operation, the idling port being positioned so that the lcoolingseiect of the vaporizing idling fuel is not transmitted readily to the throttle plate and icing of the throttle is thereby retarded or prevented.

In modern carburetors, it is conventional to provide an idling:l port which is located immediately abreast the edge of the throttle valve when closed so that as the throttle isopened, more of the port is exposed directly to engine suction and, accordingly, the fuel supplied through the port is increased to insure the formation of a combustible mixture with the increasing quantity of air which passes the throttle.

With this location of the idling port, the vaporizing of the idling fuel, particularly. lust after starting under low temperature conditions, cools the throttle plate so that ice may form thereon which may clog the port and otherwise undesirably affect the carburetor operation.

If the idling port is located wholly posterior to the throttle, although .an adequate mixture may be supplied for dead idling operation, thisl mixture would become sharply leaner as the v throttle is opened because of the decreasing suction applied thereto accompanied by increasing air flow. The result would be that for. slightly open positions of the throttle valve, the mixture supplied by the carburetor would be too lean to burn in the engine cylinders.

It-is an object of the present invention to provide 'an idling system which discharges sumciently beyond the throttle plate to eliminate icing of the throttle as the result of vaporization of the idling fuel and provided with means to increase the supply of idling fuel as the throttle is opened so as to insure thevformation of a combustible mixture.

This object and other more detailed objects areA attained substantially by the device illustrated l claim. (ci. vzel-t1) fold (not shown) and is controued by a buttery throttle valve i0 mounted on a shaft il on which is secured the usual throttle lever (not shown) for connection to the accelerator pedal in the drivers compartment. Adjacent the mixture conduit there is a fuel bowl l2 within which `fuel is maintained at a substantially constant orifice element I9 is located in the lower portion ofA bowl I2 and communicates with passages 2t and 2 I, the latter opening into the mixture conduit through a port 22 located substantially posterior to the throttle plate I2. The idling passage is provided with a restricted air bleed opening 23 and fuel restrictions 26 and 25. Metering orice I5 is controlledby a metering pin 28, having a lower graduated portion extending through the orifice, and is pinned at its upper end to a' lever 29 pivotally supported on top of the fuel bowl. The opposite end of lever 29 is connected by a link 30 to an arm 3| rigid with throttle shaft II. Orifice element I9 in the idling passage is controlled by a second metering pin 32, having a tapered lower portion extending through the oric'e, and is pinned at its upper end to a second lever 33 pivoted above the top of the fuel bowl.

. The inner end of this lever isV connected by a link 34 to throttle arm 3|.

In operation, when the throttle plate is in the fully closed position, as in Fig. 1, engine suction is applied to idling port 22 to draw a rich mixture of fuel and air into the engine. At this time little or no air passes the throttle plate so that main nozzle Il is inoperative and metering pin 32 will be lowered to a position to bring a relatively large portion thereof into the metering orifice so as to provide just sumcient fuel for idling operation. As the throttle is opened slightly, the air flow past the throttle and also past nozzle il increases. but is not yet sufilcient to draw fuel from the main nozzle. To provide for this increasing air ow, metering pin 32 is lifted by linkage 34, 33 to bring a smaller portion of the pin into the orifice, thus increasing the effective size thereof and, consequently, the quantity of fuel drawn through the idling system. When the throttle is opened further, toward the position as in Fig.- 2, fuel will start to discharge from the -be positioned in orifice I8.

main nozzle and. thereafter, most of the fuel come from this source and the idling discharge` -becomes negligible. `In the throttle position The independent idling arrangement, as shown. wherein the idling and main fuel passages communicate with the fuel chamber through separate metering orinces. is particularly advan-` tageous in connection with the non-icing arrangement of the idling fuel port. However. varfous features of the carburetor as shown are not essential and these may be modified as will occur to those skilled in the art without departing from the spirit of the invention and the exclusive `use of all such modifications as come within the scope of the appended claim is contemplated. e

I claim:

In a carburetor, a mixture conduit. a choke and of pin l2 may 4 a throttle valve in said fuel chamber, a main fuel passage extending from said fuel chamber and discharging into said mlx` ture conduit through an opening anterior to said throttle. a metering oriilce communicating with said main fuel passage. a metering pin controlling said main fuel orifice, an independent idling fuel passage extending from said fuel chamber and discharging into said mixture conduit through a port spaced substantially posterior to said throttle valve when the latter is in its closed position. the spacing of said idling fuel port from said throttle being s0 arranged that the vaporization oi' the idling fuel therefrom will take place wholly beyond said throttle valve to avoid icing the same, a metering orice in said idling passage, a stepped metering pin for said metering orifice, and a connection between said last named metering pin and throttle, whereby the supply of idling iuei will gradually increase with the movement oi the throttle toward open position.

GEORGE M. BICKNELL.

conduit, a iioat controlled l 

